In (info "(coreutils) Character sets")
‘\OOO’
The 8-bit character with the value given by OOO, which is 1 to
3 octal digits. Note that ‘\400’ is interpreted as the
two-byte sequence, ‘\040’ ‘0’.OK but do add hex too. Hmm, I probably reported this before but can't tell because I'm offline while I'm writing this, and it is too important anyway for me to check vs. mentioning again.
